Tony D

" This engine was breathing enough air to produce this 1100+ HP and was doing so through only TWO 2” ID throttle valves, EXACTLY like the 2” ID OE L-28 EFI throttle valves with full diameter throttle shafts etc." The Nissan VG30 in the #75 IMSA car run in the 90's (Z32) ran smallish throttle bodies, but the really amazing thig was they made 1100 HP, without restrictions. The IMSA rules required them to run 26mm restrictions on the turbos, and with those the engine made 'only' 750, but talking with Steve Millen, he said the Torque was really helped by this restriction, making the car much more driveable, and much more tractable coming out of corners. Where you have the restriction is as important as the size some times. Larger throttle area magnifies tip-in response, and on humongo bodies really requires non-linear response to make it driveable at all. After a certian point, it's just minimizing inlet restriction, but as has been noted velocity and manifold design will dictate how the dynamics work in any system. The Barrel Throttle Bodies available to replace 'Weber DCOE' style throttle bodies show some very interesting design features. The 45mm Barrel Throttles will have the ultimate flow equivalent to 48mm Standard Butterfly setups (thanks to no throttle shaft blocking airflow at WOT), but have tip-in response similar to 40mm Butterflies up to around 15% throttle opening. They taper the opening of the barrels to give tip-in that allows drivability, yet without compromising ultimate airflow.

Mill a flat across the runners, then mate a square log to the manifold using some through-bolts. Seal each opening into the runner with an o-ring. Looks integral with the manifold, and the volume of the 'log' will dampen strong pulsations nicely. E-Motive and most ECU manufacturers recommend a 1/2" diameter tube for the log... You could even use fuel rail extrusion for the 'log' if it's of sufficient diameter. FET Kyukto made a manifold that looked like this (but was unitized cast), but I'm at a dearth of photographic evidence to support my claim.

witch is the rite way to wright right? Wait, did I get that write?

I like the valve cover. As for all the writing... Advertising! Allows any money expended on this effort be written off against shop profits as 'advertising' thereby decreasing tax liabilities. It's why you see all the Real Estate Dudes with static cling decals (duh, 'magnetic'?) on the doors of the cars. Double dipping...

BAH! Now you live in the world of DOHC where you can surface grind all your bucket spacer/shims to adjust for valve recession...instead of simply turning a wrench! But that's an improvement! LOL Our equipment uses surface ground shims to set clearances as well...if the rotor assembly is off more and 0.005", we are off with a set of shims to find a local shop with a decent surface grinder. "In the old days" they were set up with an allen jackscrew and a locknut...but apparently the incidence of people not knowing how to properly torque a locknut resulted in too much warranty work...so in came the shims. I still open up older units and find the original locknut/jackscrew setup, and have to dissassemble the whole thrust bearing assembly to retrofit the 'new and improved' solid spacer. Better measure right the first time...you overgrind that shim and you're calling to explain 'why you need another one'---it usually gets blamed on incompetent machining! LOL I was hoping they were already ground with some performance lift/duration. Well, at least you can independently adjust your lobe centers...that should really help with the turbo and any reversion problems. As well as allow you to move the powerband pretty much where you want, within reason. Damn, that reminds me, I need to talk to Ron about my camshaft---or actually Franks. I need to get by his shop and pick it up! BEFORE I leave for Belgium. Have fun at JCCS with that thing, I'm sure the Japanese Press Boys will be pressing for interviews and feature articles for some of the JDM Magazines. It's neat when you get into one of them with your car, they will usually send you a few copies... It's too late now for CarBoy's Annual L-Engine Shootout Issue (usually October) if they even do it any more...

If the chain were to drop into the nether of the front cover, you already had the engine at #1 TDC, no? And the cam would therefore be positioned properly anyway, no? It would be a simply matter of fishing it up and attaching it, be damned where the 'bright link' ends up. If the crank and cam are in proper relation to each other when the chain is threaded to the sprockets, it will retain the proper relationship regardless of what the position the 'indicator links' assume. What you notice after installing one of these is cam timing is absolutely rock solid. The 2-5* slop from the slack chain is gone, and rotating the engine forward OR backwards results in INSTANT movement noticable on your indicator. Frankly, with one of these, I would line up the parts, and string the chain on and forget about it. There is no slop to allow enough timing alteration to affect the cam as there is with the 'oil shoe' setup. Like Alan mentions, on the S20 it is not uncommon to see a string holding the chain. Sure, it would be great if the 'bright links' lined up and made cursory visual inspections a snap...but really, if you are concerned about your cam's position, you will NOT rely on the 'bright link'...you will affix your degree wheel, rotate the engine by hand, and indicate with a suitable clock-gage and spindle arrangement to verify opening and closing events to your original setup notes. This way, you can insure, to the fraction of a degree how much your chain has stretched. This is the way I did it on my Toyotas, VW's, and Corvairs---each of which either had roller chain and manual tensioner or direct gear drive. The original Datsun "Oil Shoe" setup was about as sloppy in my eyes as the OEM Chevy Timing Chain setup---2-5 degrees slop...just terrible when compared to the aforementioned engines that used gears for driving the cam. The more precise you can make your cam timing, the better. I mean, if VW Beetles have less timing variation than your 'sports car engine'...what is THAT saying about engineering? LOL

There were some efforts early on in Datsun Turbo Development to use a linked throttle body to dump boost because of the defficient/inefficient turbo designs present at the time. If you will recall, E-Motive ran a twin turbo setup without much success, going back to a single for the 83 car, and had much better success. But they had some seat time with the new 'TEC1' that was developed. On older, inertia-soaked wheels, a blowoff such as I'm describing was the only way to insure the minimum of turbo lag (actual re-spin time) was kept to an absolute minimum. In today's cars of titanium wheels, ceramic ball bearings, and electronic controls, many other things can be done to help keep the thing spinning fast (if not even producing boost under drop-throttle conditions as Datman points out!)... But this does not mean that a properly designed blowoff won't help the situation, either. "We digress..." I'm counting my days left till I hop the plane for Spa and attend the 6-Hour.....

You haven't been following the "My official L31DETT Thread" by 1FastZ, have you? In all this time, though, truthfully, the expense of the DOHC has not been justified in the performance it delivers compared to a properly prepared SOHC head. Just because everybody seems to be doing it, doesn't mean that necessarily it HAS to be done. A properly ported and polished Non-Crossflow Head will allow 320+Hp to the rear wheels on an L28 bored 040" (at least in our case it does, some may make more with larger engines). Exactly how much more performance is needed, and more importantly, at what cost? Each of the heads proffered: LY, TC24B-1, and Blake Machine L31DETT are all in the $30,000+ range. Are you willing to pay that for 1) 5% increase in breathing, and performance increase 2) Mere Bragging Rights on a "Cool One-Off"? If you are, I'm sure Bryan can make a head up. And Alan's price is a BARGAIN! Last one I saw 'sell' on an auction site was bare and $4K more!!! So a general area price of $30K for an LY should put you in the ballpark for the incomplete part... For $10,000 Rebello or SunBelt will make a complete engine that will be competitive on horsepower and drivability scale...leaving you another $20K to spend on a chassis that will competently and easily handle the power you will produce. So paraphrasing Harry Callahan: "So you gotta ask yourself, do I want a Head, or to I want the whole package? And if I want the Head...will I be able to get the rest of the pieces, or only some of them. And even if I get all of them, will it hold together after all this time? You gotta ask yourself, do you feel lucky?" Like someone out of the first scene in "Dirty Harry", some will still say: "I gotsta know!" And in manny cases the outcome will be the same: "DAMN!";) ******************************************************************************************* On an aside, it's not that they haven't developed an aftermarket head, it's that most simply are ignorant of their existence. And that they were in existence almost 30 years ago, doesn't help either! The engine is not all that popular, when you consider total volume production. The Ford Flathead had all sorts of heads running around, but who today buying their first car would think anything of 'ARDUN' on the head of the old jalopy they just towed out of the cornfield in Bakersfield? For that matter, Schubeck on SBC? The stuff is out there, but usually is addresses a serious deficiency in the designs of the original heads. Lacking a serious design flaw...the market dwindles because it's simply easier to make the ports flow what you want than to redesign a whole complex head!

Were those stock, or performance-reground cams, Bryan?

Why do I hear John Belushi's haunting recital 'Wolf's Head Premium, I've always used Wolf's Head Premium Oil in her!' after reading that reminisce! LOL Interesting Additive Information. I know a lot of the Engineers were scared about centrifuging out the additive package when I installed oil cleaning turbines at the plant I ran in Brea. It was unfounded. We actually had pretty good luck with additive packages to supplement the base stock of oils when our fuel stock went acidic, and our TAN for the weekly oil analysis would drop below 4 in less than 1000 hours of run time! No choice: Batch Additive, or etch the bearings until we could get our original oil back into the engines (Mobil Blackstar). I don't even think Blackstar is available any longer, I think it was supersceded by the Pegasus line of Diesel Lubricants...or Delvac. Pegasus sucked compared to Blackstar...that stuff was awesome! Then again, it was 14-17 Years ago, eh?

I don't know the conductivity number. It is related, but you can get litmus strips cheaply and it gives a good indication of basic/acidic. A conductivity test will tell you about free electrons in the water, something that can effect corrosion, but it can be either basic or acidic...of course free electrons with a basic solution will not be a real problem, but excess free electrons in an acidic environment will cause runaway corrosion! The tests go hand in hand, and NOBODY should be running their anti-freeze more than a year or two, regardless of what the litmus paper says!!!

Thanks for that Braap, I have posted a blurb on "Machinist's Quandaries" in the other thread saying about the same thing. The reward is the process, as the goal is set so high. When you set high goals, failure is a noble effort. When you set middling goals, failure or success is...well...mediocre.

Some people have a problem grasping a Machinist's Quandary. Why does a machinist make a round ball captive within a cubic form? Why does a machinist make a chain from a solid bar stock? There are countless Machinists' Quandaries out there, and the reason to do them is always the same: To do them. The thought and engineering that goes in to the front end of the Quandary is the reward. It makes the machinist think, actually think about what the project will need to be brought to fruition. I said it elsewhere, this is not a narcissistic trumpeting of his accomplishments, but rather an informative blurb on what he is doing , and why.

Appearing Next Spring? What happened to the Marines? Oops!

Someplace there is a photograph of that Bronco II surge tank cut apart. it may be at Zcar.com I don't see anything in my 'favorites' but someone cut one apart and marked up the photo really nice so you could figure it out. Seem to recall they found the part number, went to the junkyard to find one to cut apart, then satisfied it would work, bought a new one. That scenario was what I was basing my recomendations on in the past. It will be a bummer if these parts are going to be NLA... As you can see it's a nice piece.

If you drop all restriction, and bypass the compressor so it's in a 'vacuum' the decrease in wheel speed is MUCH different than if you are actually pumping air. WRC Cars do use retard, but that is because they are 'flat shifting' at WOT and using pretty sophisticated ECU interactions to control the ignition to turn the exhaust manifold into a gas turbine combustion can, powering the turbine differently than when on normal boost. You are actually engaging in combustion in the manifold, not in the combustion chamber... What we are talking about is a 'lift throttle' situation where turbine energy is decreased, and at the same time you drop pumping air on the compressor end. This allows basically a 'free float' of the wheels with very little deceleration, if any. If you alter timing at the same time, you would need far less retard because it is operating in a 'bypass' as well as 'free field' mode of compression.

I know of only two TC24B-1 heads that I have personally seen, and laid hands upon. LY heads, as Alan has mentioned, are much more 'common'...if that word applies. Seen several of them, turned down the opportunity to buy one for $1000 in 1988 (D'OH), and have a line on three new in box, never been used complete examples that I will be heading to check out very, very soon... The LY is just too cool, and when it comes down to it, is an OEM head with OEM reliability, and OEM R&D Testing behind it...giving it a 'leg up' in my mind over aftermarket offerings. Then again, adding to my list of Z-Car Blunders the declination of the LY Purchase was BY FAR not the worst...declining to buy a 432 in 1985 for $3200 using the logic of 'I can get anny Fairlady with a Two-Year Inspection on it for $1800, what makes that one worth 2X as much?!?' Then, adding insult to injury, I find out the car in question (again offered to me as a TRADE for my 73 240Z straight across) had a Grand-Slam GT-R 2.2 Bore-Up Kit, a set of Mechanical FI cams, as well as several rocekt boxes of spares to include another engine (complete)...well....coulda woulda shoulda... I had already filled out my Governmental Shipping Documents in Triplicate and there was NO WAY they were going to believe I mistakenly put down 'HLS30-156466' that many times as a 'mistake'... Same guy still owns the 432, and I still own the 73...

Bleah! They put the North American Steering Wheel on the thing! BLEAH! Otherwise, nice car, GS31, ZL. But that steering wheel needs to go!

Most industrial guidebooks say that anything more than 20% EG will effect heat transfer, so on stationary compressors or other equipment in closed-loop systems we will try to use water with treatments when at all possible, and no more than 20% E-G for maximum heat transfer/inhibiting. Drewguard from Drew Chemicals will inhibit corrosion and make a nice, tanish phosphate coating on exposed metal that prevents bad corrosion, but I don't know that it comes in anything but a 55 gallon drum! One thing EVERYBODY should do, is test their coolant with a Litmus Strip. You should be slightly basic (above 7.5) Usually 7.5 to 10 is what you will shoot for... If it's below that point, it's acidic (duh) and will exacerbate the dissimilar metals (alunminum / cast iron) issue as well.

Sniff, Sniff, I smell Jealousy at someone's DETT project firing up and running... On the accelerative mass issue, the responsiveness of the engine is directly related to the weight of it's components. What should have been done in conjunction with the weight reduction of the pistons, was an equal reduction in the crankshaft counterweight as it does not now need such a large overhanging weight to 'counteract' the stock weight. The pistons are 150 grammes less than stock, and of a stronger material. It is possible that this setup is more durable than stock! It wouldn't be the first time material thicknesses were reduced without any effect on overall part longevity...and I can point out in some bearings where superior metallurgy was used to greatly reduce thicknesses of races with absolutely no reduction in B-Life.

Yes, I was serious, kids broke out a window and a tom cat used it for a love nest, spraying liberally. It has been airing out for years, and STILL stinks like cat's p... That is an interesting intake/engine setup. The Fast Idle for the A/C is unique, and totally a different setup than my car which was less than 1000 cars later down the production line. I have a stepper motor for idle control under the T/B, and no cold-start valve. Verrrry Interesting!

Wow, Nissan jobber price was only $146 not a few years ago. My understanding is the 432 Grilles are gone, but the other Fairlady Z grilles are still available from most any Nissan Dealer if you give them the part number..

Like I said, it only takes proper controls! Once the turbo is up on the boil, there really is no reason not to dump excess in copious volumes rather than let it slow and re-spin to optimum speed. The throttle response on-boost is much better doing it that way.

The GRS30 in basic form is actually very close to, if not lighter than a US Coupe of the similar Vintage. My 75 GS31 weighed in at 2695# with my 255# butt in it. Do the math, and there are some pretty suprised HLS30 owners out there! That's with the full ZS interior in it, including spare tyre... Like someone said, 'they aren't as heavy as you would think' Of course, I don't have door beams in the door. Oh well, I'm more careful turning left across our US Traffic as a result (since it's RHD!).

One thing Corvair people would do is trim those pinchweld flanges. Working on the Z, you can see statistical designing and manufacturing processes firsthand in the small pinchweld flanges. On a Corvair it was not uncommon to cut 20-30# from the Unitbody by trimming the pinchweld flanges (Marc Natale said he cut 33# of metal out on his 67 Monza that he ran up at Willow Springs, black car if anybody ever saw it in the 90's)...some of them are 1" WIDE! Mmmmm, production variation. When they were welding the chassis with Oxy-Acetylene, you could see the guys using very little rod, and using the longer pieces of the flange to melt down and become filler for the shorter pieces in the stackup. Other places would grind down the pinchwelds until all pinchweld pieces are even, and no one component is higher or shorter then the other, then they weld them. I really didn't see them cut the Datsun flanges down that much if at all...maybe a mm or two. On the Corvairs some times you would use a Sawzall and cut 1/2 to 3/4" off a flange, and then go back and weld it because some of the spotwelds were out on the far edges of the flange---imagine that in regards to flex! Nothing irritated me more than to see spotwelds on the EDGE of the flange, half on the metal, and missing one,two, or three panels of a four panel sandwich! Argh!